Electrophotographic printers produce images by depositing toner on receivers (or “imaging substrates”), such as pieces or sheets of paper or other planar media, glass, fabric, metal, or other objects. Printers typically operate using subtractive color: a substantially reflective receiver is overcoated image-wise with cyan (C), magenta (M), yellow (Y), black (K), and other colorants. Other toner compositions can be used to produce effects beyond simple image appearance.
For example, U.S. Publication No. 20080159786 by Tombs et al., entitled “Selective printing of raised information by electrography,” published Jul. 3, 2008, the disclosure of which is incorporated herein by reference, describes electrophotographic printing using marking particles of a substantially larger size than the standard size marking particles of the desired print image. These particles are referred to herein as “dimensional” particles. Tombs et al. also describe using non-pigmented (“clear”) marking particles to overlay raised information on an image. This technique is very useful. For example, clear dimensional (“DMCL”) particles can be used to produce tactile effects, such as textures a viewer feels when he touches an image printed on a receiver.
WO 90/07753 by Small et al. and GB 2 284 319 by Tompkins et al. describe a job image buffer (JIB) that stores compressed image data in memory until it is to be printed.
U.S. Pat. No. 5,984,446 to Silverbrook describes a drop-on-demand inkjet printer with a band-by-band page image compression system, and U.S. Pat. No. 6,002,847, also to Silverbrook, provides more detail of a compressed-image storage apparatus useful with that printer. The '847 reference describes JPEG compression of pixel data. This reference also points out that JPEG compression of high-frequency patterns can add noise to the image.